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This specification establishes the requirements for power operated hydraulic servoactuators when used in flight control systems. These servoactuators may be controlled by mechanical, hydraulic or electrical inputs or combinations thereof, and may be powered by one or more hydraulic systems. The complete servoactuator package may incorporate primary components such as control servovalve, input linkage and position feedback lever in addition to the actuating cylinder. Secondary components may also be included such as stability and control augmentation actuators, bypass valves, residual pressure compensators, electrohydraulic servovalves, filters, pressure switches, motor or solenoid operated shut-off valves, thermostatic control valves, hydraulic logic, mechanical locking devices and electrical transducers.

There is a need to guide component designers and system integrators in the development of specifications for Synchro/Resolvers that are used for positional measurement in aerospace applications. This document addresses that need.

This Aerospace Recommended Practice (ARP) offers guidelines for specifying servoloop pressure feedback transducers for use in hydraulic actuation for servosystems.

This Aerospace Recommend Practice (ARP) offers guidelines for the development of hydraulic actuation system models and simulation. Guidance is provided in the process of specifying, developing, and validating the models.

Various gas systems are classified in a broad sense, component operation is described in moderate detail, pertinent design parameters are discussed, and possible modes for system operation are listed.

Various gas systems are classified in a broad sense, component operation is described in moderate detail, pertinent design parameters are discussed, and possible modes for system operation are listed.

This SAE Aerospace Recommended Practice (ARP) provides guidance in the design, development, qualification test, process control and production acceptance test for flight critical control valve (FCCV) design used in military flight control servoactuators where loss of single valve control could cause a catastrophic failure resulting in death, permanent total disability, and/or financial loss exceeding a defined contractual limit. The FCCV, which is one element of a flight control actuator servo control loop, is a variable position control valve which modulates fluid into and out of the servoactuator power stage cylinders. The FCCV may be mechanically driven by either a mechanical flight control system as shown in Figure 1 or hydraulically driven from electro-hydraulic servo valve (EHSV) modulation control flow as shown in Figure 2. This type of control valve is not an EHSV or a direct drive valve (DDV). The FCCV is used in military hydraulic systems which conform to AS5440.

This SAE Aerospace Recommended Practice (ARP) provides definitions and background information regarding the physical performance and testing of electrohydraulic flow control and pressure control servovalves. This ARP also provides extensive guidance for the preparation of procurement specifications and for functional testing. NOTE: An example of a procurement specification is provided as Appendix A.

This SAE Aerospace Recommended Practice (ARP) provides definitions and background information for understanding the physical performance, and test procedures of electrohydraulic flow control servovalves. The recommendations are confined to interface definition and input/output characteristics. This ARP does not restrict or attempt to define the internal characteristics of servovalves. As such, the recommendations are equally applicable to valves having different internal functioning, different ratings, different physical size, and valves used with different fluids. In certain instances, standards for valve design are recommended for the purpose of interchangeability, as for example, valve polarity, mounting bolt and fluid port locations. The ARP provides extensive guidance for the preparation of Procurement Specifications and for functional testing. A sample Procurement Specification is provided in Appendix A. The primary focus of this ARP is on four-way valves.

The recommendations contained herein are confined to the input and output characteristics of electrohydraulic mechanical feedback servoactuators. The information presented should be useful for standardizing the terminology and for specification of physical and performance parameters. The recommendations do not restrict nor attempt to define the internal design characteristics of servoactuators. As such, the material is equally applicable to servoactuators having different internal functioning, different ratings, different physical size, etc. In certain instances, standards for actuator design are recommended to increase interchangeability as, for example, pigtail color-coding and actuator polarity. The specifications contained herein should be adequate to describe electrohydraulic mechanical feedback servoactuators used for position control. Additional specifications may be necessary to define special requirements for specific control systems.

This recommended practice is intended as a guide for the specification of electrohydraulic mechanical feedback servoactuators used for position control. It provides performance definitions and capabilities that are specific to mechanical-feedback servoactuators and different from those applicable to electrical-feedback servoactuators.

This SAE Aerospace Recommended Practice (ARP) is intended as a guide to aid in the specification and testing of electrohydraulic servovalves. The recommendations contained in this ARP are confined to the input and output characteristics of electrohydraulic servovalves, the primary focus being four-way flow control servovalves. Three-way flow control servovalves are discussed to a limited extent, and terminology recommended for use with pressure control servovalves is also presented. The information presented should be useful in standardizing the terminology, the specification of physical and performance parameters, and the test procedures used in conjunction with these components. The recommendations do not restrict nor attempt to define the internal design characteristics of servovalves. As such, the material is equally applicable to servovalves having different internal functioning, different ratings, different physical size, etc.

The recommendations contained herein are confined to the input and output characteristics of electrohydraulic mechanical feedback servoactuators. The information presented should be useful for standardizing the terminology and for specification of physical and performance parameters. The recommendations do not restrict nor attempt to define the internal design characteristics of servoactuators. As such, the material is equally applicable to servoactuators having different internal functioning, different ratings, different physical size, etc. In certain instances, standards for actuator design are recommended to increase interchangeability as, for example, pigtail color-coding and actuator polarity. The specifications contained herein should be adequate to describe electrohydraulic mechanical feedback servoactuators used for position control. Additional specifications may be necessary to define special requirements for specific control systems.

The recommendations contained in this ARP are confined to the input and output characteristics of electrohydraulic flow-control servovalves. The information presented should be useful in standardizing the terminology, the specification of physical and performance parameters, and the test procedures used in conjunction with these components. The recommendations do not restrict nor attempt to define the internal design characteristics of servovalves. As such, the material is equally applicable to servovalves having different internal functioning, different ratings, different physical size, etc. In certain instances, standards for valve design are recommended to increase component interchangeability, as, for example, pigtail color-coding, valve polarity, mounting bolt and fluid port locations. The specifications contained herein should be adequate to describe electrohydraulic flow-control servovalves.

The recommendations contained in this ARP are confined to the input and output characteristics of electrohydraulic flow-control servovalves. The information presented should be useful in standardizing the terminology, the specification of physical and performance parameters, and the test procedures used in conjunction with these components. The recommendations do not restrict nor attempt to define the internal design characteristics of servovalves. As such, the material is equally applicable to servovalves having different internal functioning, different ratings, different physical size, etc. In certain instances, standards for valve design are recommended to increase component interchangeability, as, for example, pigtail color-coding, valve polarity, mounting bolt and fluid port locations. The specifications contained herein should be adequate to describe electrohydraulic flow-control servovalves.

The recommendations contained in this ARP are confined to the input and output characteristics of electrohydraulic flow-control servovalves. The information presented should be useful in standardizing the. terminology, the specification of physical and performance parameters, and the test procedures used in conjunction with these components. The recommendations do not restrict nor attempt to define the internal design characteristics of servovalves. As such, the material is equally applicable to servovalves having different internal functioning, different ratings, different physical size, etc. In certain instances, standards for valve design are recommended to increase component interchangeability, as, for example, pigtail color-coding, valve polarity, mounting bolt and fluid port locations. The specifications contained herein should be adequate to describe electrohydraulic flow-control servovalves.

The recommendations contained in this recommended practice are confined to the input and output characteristics of electrohydraulic flow-control servovalves. The information presented should be useful in standardizing the terminology, the specification of physical and performance parameters, and the test procedures used in conjunction with these components. The recommendations do not restrict nor attempt to define the internal design characteristics of servovalves. As such, the material is equally applicable to servovalves having different internal functioning, different ratings, different physical size, etc. In certain instances, standards for valve design are recommended to increase component interchangeability, as, for example, pigtail color-coding, valve polarity, mounting bolt and fluid port locations. The specifications contained herein should be adequate to describe electrohydraulic flow-control servovalves.

In this document a servovalve is defined only as a valve, normally used in a servomechanism which has a hydraulic output (flow, pressure) which is a function of an electrical input (voltage, current, differential current). This ARP will confine itself to describing those parameters which are peculiar to such valves.

This SAE Aerospace Recommended Practice (ARP) describes the design conditions under which tests should be conducted to demonstrate satisfactory performance of a flight critical servo-actuator under the maximum allowable particulate contamination in the associated airplane hydraulic system. Additionally, this document also describes the recommended tests and the required acceptance criteria.

This SAE Aerospace Recommended Practice (ARP) is intended as a guide to aid in the specification and testing of Direct Drive Servovalves, but does not include the associated electronic controller. The recommendations contained in this ARP are primarily confined to the input and output characteristics of Direct Drive Servovalves (DDV). The only exception to this approach involves the definition and specification of chip shear force, which is not typically measurable by nondestructive external testing. The information presented should be useful in standardizing the terminology, the specification of physical and performance parameters, and the test procedures used in conjunction with these components. Direct drive servovalves are of two basic types: open loop and closed loop. In the case of open loop direct drive servovalves, the significant input is the motor current as is the case with electrohydraulic servovalves covered in ARP490.